Idiopathic Thrombocytopenic Purpura (ITP)

Overview

What is ITP?

ITP stands for idiopathic thrombocytopenic purpura. "Idiopathic" means that the cause of the condition is unknown. "Thrombocytopenic" means the blood doesn't have enough platelets (platelets are also called thrombocytes). "Purpura" means a person has excessive bruising. ITP is also sometimes called "immune thrombocytopenic purpura."

In people who have ITP, all of the blood cells are normal except for the platelets. Platelets are the tiny cells that form blood clots and seal minor cuts and wounds. A person who has too few platelets bruises very easily and can bleed for a long time after being injured. When the platelet count is very low, a person who has ITP might have nosebleeds that are hard to stop, or they might have bleeding in the intestines, or even bleeding in the brain with minor trauma.

How does ITP affect children?

ITP in children is usually mild and runs it course without the need for treatment. About 80% of children recover completely from ITP within about 6 months.

Symptoms

What are the symptoms of ITP?

The symptoms of ITP include:

Easy or excessive bruising

Petechiae (tiny reddish purple dots on the skin that are caused by bleeding under the surface of the skin) on the body, especially on the lower legs

Cuts or minor wounds that take a very long time to clot or stop bleeding

Blood in the urine or stools

Unusually heavy menstrual flow in women

Unexplained bleeding from the nose or gums

Many adults have only mild thrombocytopenia. In fact, quite a few people have no bleeding symptoms. In most adults, ITP lasts much longer than it does in children. At the time of diagnosis, most adults have noticed increased bleeding and easy bruising for several weeks or even months. In women, increased menstrual blood flow is a common sign.

Causes & Risk Factors

What causes ITP?

The cause of ITP is not known. People who have ITP form antibodies that destroy their blood platelets. Normally, antibodies are a healthy response to bacteria or viruses. In people who have ITP, however, the antibodies attack the body's own blood platelets.

Who gets ITP?

There are 2 types of ITP. One type affects children, and the other type affects adults. In children, the usual age for getting ITP is 2 to 4 years of age. Most adults with ITP are young women, but it can occur in anyone. ITP does not seem to be hereditary (run in families). ITP is not contagious (you can’t “catch it” from someone else).

Diagnosis & Tests

How is ITP diagnosed?

Your doctor can begin to diagnose ITP by asking questions about your health and doing a physical exam. Your doctor may take a blood sample for a test that counts blood cells and platelets (called a CBC) or look at it under a microscope (called a blood smear). Your doctor may also want you to get a bone marrow exam to rule out other possible causes of your symptoms.

Many adults are only diagnosed with ITP when their blood is checked for another reason and a low blood platelet count is found.

Treatment

How is ITP treated in adults?

Mild cases of ITP may not require treatment, just regular monitoring of the platelet levels.

Otherwise, treatment of ITP in adults is aimed at increasing the blood platelet count. This is not the same as curing the disease. Your doctor may recommend that you get high doses of immune globulin (through a needle). Some patients might take prednisone for several weeks or months. Prednisone raises the level of your platelet count. As your count rises and reaches a safe level, your doctor may gradually decrease your medicine until you no longer take the prednisone. However, when the medicine is stopped, your platelet count may decrease again.

If prednisone doesn't help enough, your doctor may recommend that your spleen be removed. The spleen makes most of the antibodies that destroy the blood platelets. It also destroys old or damaged blood cells. In an otherwise healthy person, removal of the spleen is not a serious operation. Laparoscopic removal of the spleen is now possible, further reducing surgical risk. However, this treatment is done less often than it once was. Removing the spleen will permanently reduce your body’s ability to fight infection. Some people can also relapse (have the condition return) even after the spleen is removed.

Other treatments for ITP include another kind of steroid medicine called danazol or other medicines that work to hold the immune system in check, such as rituximab. Some people with certain blood types may have anti-RhD therapy, which is a shot or series of shots that also work to reduce antibodies in the blood. Another option includes filtering antibodies from the blood.

How is ITP treated in children?

Because most children recover with no treatment, many doctors recommend just watching them carefully and taking care of the bleeding symptoms. Children don't have to go to the hospital if good care is available at home. However, some doctors recommend a short treatment with prednisone pills or intravenous infusions (given in a vein) of gamma globulin to increase the platelet count more quickly. Both medicines have some side effects.

What can I do if I have ITP?

If you have ITP, you should avoid medicines that increase risks for bleeding, such as warfarin (a medicine often used to treat an abnormal heart rhythm called atrial fibrillation) and over-the-counter drugs like aspirin and ibuprofen (some brands: Advil, Motrin). You should also limit alcohol because it can decrease the ability of your blood to clot.

Complications

What about ITP in pregnant women?

Many of the medicines used to treat ITP should not be taken by women who are pregnant. Talk to your doctor if you are taking medicine and want to become pregnant.

Diagnosing ITP during pregnancy can be difficult, because platelet counts may be low for other reasons. About 5% of women have mildly low platelet counts at the end of a normal pregnancy. The cause of this is unknown. The platelet count goes back to normal right after delivery.

A baby born to a mother who has ITP may have a low blood platelet count a few days to a few weeks after birth. These babies are usually kept in the hospital for several days for observation (watching to make sure they are okay) before they go can home. If the baby's platelet count is very low, treatment is available to speed recovery.